In a rare occurrence, Tim Cook has spoken out in support of the pending Employment Nondiscrimination Act. The CEO penned an open letter, which ran in the Opinion section of The Wall Street Journal last night, urging Congress to approve the END Act.

The legislation would prohibit a number of civilian, non-religious companies in the US from discriminating on the basis of sexual orientation or gender identity. And in his letter, Cook explains that a safe welcoming work environment is good for business…

“At Apple, we try to make sure people understand that they don’t have to check their identity at the door. We’re committed to creating a safe and welcoming workplace for all employees, regardless of their race, gender, nationality or sexual orientation.

As we see it, embracing people’s individuality is a matter of basic human dignity and civil rights. It also turns out to be great for the creativity that drives our business. We’ve found that when people feel valued for who they are, they have the comfort and confidence to do the best work of their lives.

Apple’s anti-discrimination policy goes beyond the legal protections U.S. workers currently enjoy under federal law, most notably because we prohibit discrimination against Apple’s gay, lesbian, bisexual and transgender employees. A bill now before the U.S. Senate would update those employment laws, at long last, to protect workers against discrimination based on sexual orientation and gender identity.”

While Cook is more vocal on workplace equality than Steve Jobs ever was, Apple’s support of it isn’t anything new. The company has long offered health benefits to employees in same-sex relationships, and in 2008 it donated to the “No on Prop 8″ campaign.